Restorative surgery has long had the difficult task of finding replacement materials for use as fillers, grafts and connectors in the practice of the specialty. In this practice, as well as in many other aspects of medicine, the body's superbly designed defense mechanisms present a challenge to the physician's task of intervening and manipulating the body tissue to achieve a functional or an aesthetically pleasing result. To date, different methods of replacement of tissue and different replacement materials have been widely used, however, they have been, to a certain extent, unsatisfactory. Evidence of the unsatisfactory result is shown by the history of the use of silicon in breast implants. In addition to the variety of medical problems reported by the implantees of such devices, silicones are known to be problematic due to capsular contraction.
Another form of replacement has been the use of dermal fat grafts; however, such grafts have a tendency for resorption, leaving the graftee in little better condition than before the procedure. The use of bovine collagen has been attempted, but such attempts bring their own peculiar set of worries.
A soft tissue replacement for defects should have certain characteristics, including freedom from rejection, such that the body's defenses are minimized as a problem. The material should be persistent, malleable, of easy use, and free of complications from its use. Additionally, it should be of low cost.